refactor(session/store): consolidate session errors and use multi-error wrapping

pkg/session/store.go

@@ -2,7 +2,6 @@ package session
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"time"
 
@@ -11,10 +10,6 @@ import (
 	"github.com/nais/wonderwall/pkg/config"
 )
 
-var (
-	ErrKeyNotFound = errors.New("key not found")
-)
-
 type Store interface {
 	Write(ctx context.Context, key string, value *EncryptedData, expiration time.Duration) error
 	Read(ctx context.Context, key string) (*EncryptedData, error)

pkg/session/store_memory.go

@@ -26,7 +26,7 @@ func (s *memorySessionStore) Read(_ context.Context, key string) (*EncryptedData
 
 	data, ok := s.sessions[key]
 	if !ok {
-		return nil, fmt.Errorf("%w: no such session: %s", ErrKeyNotFound, key)
+		return nil, fmt.Errorf("%w: no such session: %s", ErrNotFound, key)
 	}
 
 	return data, nil

pkg/session/store_redis.go

@@ -33,7 +33,7 @@ func (s *redisSessionStore) Read(ctx context.Context, key string) (*EncryptedDat
 	}
 
 	if errors.Is(err, redis.Nil) {
-		return nil, fmt.Errorf("%w: %s", ErrKeyNotFound, err.Error())
+		return nil, fmt.Errorf("%w: %w", ErrNotFound, err)
 	}
 
 	return nil, err
@@ -59,7 +59,7 @@ func (s *redisSessionStore) Delete(ctx context.Context, keys ...string) error {
 	}
 
 	if errors.Is(err, redis.Nil) {
-		return fmt.Errorf("%w: %s", ErrKeyNotFound, err.Error())
+		return fmt.Errorf("%w: %w", ErrNotFound, err)
 	}
 
 	return err

pkg/session/store_test.go

@@ -87,6 +87,6 @@ func del(t *testing.T, store session.Store, key string) {
 
 	result, err := store.Read(context.Background(), key)
 	assert.Error(t, err)
-	assert.ErrorIs(t, err, session.ErrKeyNotFound)
+	assert.ErrorIs(t, err, session.ErrNotFound)
 	assert.Nil(t, result)
 }